Efficacy of mouth opening exercises in treating trismus after maxillectomy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Patients with maxillary tumor often suffer from trismus after maxillectomy, which could turn out to be a permanent sequela without proper intervention. In this study, the efficacy of mouth opening exercises in preventing and treating trismus was observed in patients with maxillary tumor early after their operations. At the same time, radiotherapy as an influencing factor for the mouth opening exercises was evaluated.</p><p><b>METHODS</b>In this study, 22 patients with maxillary oncology began their mouth opening exercises at an early stage (1-2 weeks) after maxillectomy. They were divided into two groups based on the principle of voluntariness: 11 patients in group 1 chose TheraBites as their instruments of mouth opening exercises, and the other 11 in group 2 chose stacked tongue depressors to help their exercises. All participants were trained to exercise 3-5 times a day, 30-40 oscillations at one time, with a 2-second pause at their maximum possible mouth open position. The maximal interincisor distances (MID) of patients were measured and recorded by a single investigator every week after the beginning of the mouth opening exercises. Medical information and the responses of patients were also recorded. Initial and final MIDs were calculated by SPSS 13.0.</p><p><b>RESULTS</b>The changes of the mouth aperture every week during exercises in both groups were described in figures, and there were statistical increases in the final MIDs compared with the initial ones. However, no significant differences were achieved between groups 1 and 2 (P > 0.05). Radiotherapy seemed to have no negative impact on the mouth opening results during the exercises.</p><p><b>CONCLUSION</b>Physical mouth opening exercises should be executed early after maxillectomy for the prevention and treatment of trismus, especially for those who had radiotherapy as part of antitumor treatments.</p>

The bonding characteristic of titanium and RG experiment porcelain / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the bonding characteristic of Titanium and RG experiment porcelain.</p><p><b>METHODS</b>5 specimens with a size of 10 mm x 5 mm x 1.4 mm were cast from pure titanium. Then 1 mm of RG experiment opaque and body porcelain were fused on the surface of the titanium specimens. The interface of titanium and porcelain was analyzed with a scanning electron microscope with energy-despersive spectrometry; 6 metal specimens with the size of 25 mm x 3 mm x 0.5 mm were cast from Ni-Cr alloy and a uniform thickness of 1 mm of VMK 99 porcelain was veneered on the central area of 8 mm x 3 mm 18 metal specimens as the same size were cast from pure titanium. The uniform thickness of 1 mm of VITA TITANKERAMIK porcelain, of Noritake super porcelain Ti-22 and of RG experiment porcelain were veneered on every 6 specimens respectively in the central area of 8 mm x 3 mm. The specimens were subjected to a three-point bending test on a load-test machine with a span of 20 mm, then the failure loads were recorded and statistically analysised. The RG porcelain/titanium crown was fabricated by fusing RG opaque porcelain and body porcelain to cast titanium substrate crown.</p><p><b>RESULTS</b>The SEM results show no porosity and crackle were found in the interface. The energy-dispersive spectrometry show that there are Si, Ti and O in the 1 micro m layer between porcelain and titanium, which suggesting titanium and experiment porcelain bonding well. The three point test showed the fracture force for the combinations of titanium/VITA TITANKERAMIK porcelain, titanium/Noritake super porcelain Ti-22 and titanium/RG experiment porcelain were (7.233 +/- 2.539) N, (5.533 +/- 1.199) N and (6.316 +/- 1.433) N respectively. There were not statistically significant differences among them (t test, P < 0.01). The fracture force for the Ni-Cr alloy/VMK99 porcelain combination (12.733 +/- 3.297) N was significantly greater than those of the cast titanium/porcelain (t test, P > 0.05). The crown was translucent with no crack.</p><p><b>CONCLUSION</b>RG porcelain is well compatible with titanium.</p>